Six other soldiers believed to have been Taliban infiltrators were missing after the raids on outposts along the remote Ghaziabad highway east of Kabul.

The Taliban claimed responsibility for the attack in a statement sent to news media.

About 80 militants carried out the attack before dawn, said the provincial governor of Kunar, Shuja-ul-Mulk Jalala. He said the raids were conducted in coordination with Taliban members who were serving in the army in Ghaziabad.

"I think some soldiers were in contact with the Taliban before this incident and it has taken place with assistance by the Taliban infiltrators who were serving in the army ranks," Jalala said.

Jalala said that six soldiers whom Afghan officials reported were missing following the incident were likely Taliban members. U.S. and Afghan officials have long worried about the Taliban's ability to embed inside Afghan security forces, and have blamed infiltrators for several previous attacks on Afghan and international soldiers.

At least two Taliban members were killed in Sunday's assault, Jalala said.

Afghan President Hamid Karzai condemned the attack by “the enemies of Afghanistan” and repeated calls for the government of Pakistan to crack down on militants operating from its side of the border. Violence in Pakistan has surged in recent weeks, with Pakistani security forces launching airstrikes against suspected insurgents following the reported execution by militants last Sunday of 23 Pakistani paramilitary soldiers.

In a statement, Karzai said Pakistan should "take serious and effective measures in eliminating the terrorist sanctuaries that have continued to pose a grave and serious threat to both the countries."

Baktash is a special correspondent. Times staff writer Shashank Bengali in Washington contributed to this report.